# Agent execution, development lanes, and model resolution

AIOSON uses `.aioson/context/agent-execution-{feature}.json` to run a bounded feature task through a registered CLI host and model. The manifest is runtime configuration, not another specification.

## Defaults

A new manifest enables only:

- `dev`;
- `qa`.

`tester`, `pentester`, `validator`, and all development lanes are disabled. MICRO/SMALL/MEDIUM classification never enables them.

The canonical delivery route remains Product → Sheldon → Planner → DEV → QA. Optional development lanes execute inside DEV; optional reviewers execute after QA only when explicitly enabled and triggered.

## Commands

```bash
aioson agent:execution:init . --feature=my-feature --host=codex
aioson agent:execution:validate . --feature=my-feature --json
aioson agent:execution:show . --feature=my-feature --json
aioson agent:execution:dispatch . --feature=my-feature --agent=qa
aioson agent:execution:dispatch . --feature=my-feature --lane=backend
aioson agent:execution:resume . --feature=my-feature
aioson agent:execution:status . --feature=my-feature --json
```

Initialization is create-once. Later init, resume, and workflow seed operations preserve the developer-owned manifest byte for byte.

## Schema v2 orchestration and Neural Chain

New manifests use version 2 while version 1 remains accepted unchanged. The additive fields are:

- `orchestration.mode`: `autopilot` by default, or `inherit` / `step_by_step` when the developer changes it;
- `orchestration.max_checkpoints`: the effective Autopilot runner budget (default 10);
- `orchestration.stop_conditions`: explicit terminal reasons;
- `chain_work_policy`: kind-to-owner routing, specialist fallback, QA revalidation, and the DEV actionable-work handoff gate.

Test/security items route to Tester/Pentester only when their existing manifest entries are enabled. Otherwise they fall back to DEV. This never enables an optional specialist by classification.

## Development lanes

Use lanes only when the user or approved plan explicitly asks for different execution hosts/models or separately owned scopes.

```json
{
  "development_lanes": {
    "strategy": "split",
    "integration_owner": "dev",
    "lanes": {
      "backend": {
        "enabled": true,
        "host": "codex",
        "mode": "external",
        "model": "gpt-5.6-sol",
        "reasoning_effort": "high",
        "writable_roots": [],
        "prompt": ".aioson/context/execution-prompts/my-feature/backend.md",
        "write_paths": ["src/api/**", "tests/api/**"],
        "fallbacks": [],
        "report": ".aioson/context/reports/my-feature/{run_id}/dev-backend.json"
      },
      "frontend": {
        "enabled": true,
        "host": "opencode",
        "mode": "external",
        "model": "provider/model-id",
        "writable_roots": [],
        "prompt": ".aioson/context/execution-prompts/my-feature/frontend.md",
        "write_paths": ["src/ui/**", "tests/ui/**"],
        "fallbacks": [],
        "report": ".aioson/context/reports/my-feature/{run_id}/dev-frontend.json"
      }
    }
  }
}
```

`host` names a registered CLI adapter; `model` is the model/provider identifier understood by that host. A model such as Grok may be used through a compatible host such as OpenCode; it does not require a canonical `@frontend` or `@backend` agent.

DEV creates the short runtime prompt from the approved PRD and implementation plan, dispatches enabled lanes sequentially in the shared worktree, audits their diffs against `write_paths`, integrates shared boundaries, and runs the full planned verification. Lane reports bind the lane identity and declared paths.

Currently registered execution adapters include Codex, Claude Code, OpenCode, and Kimi Code. New hosts require a registered adapter so executable resolution, capabilities, arguments, redaction, and telemetry remain fail-closed.

## Explicit fallback only

Missing CLI, unsupported capability, or unavailable model pauses execution. The active chat must never imitate the requested model.

A fallback runs only when both the entry and the global policy authorize it:

```json
{
  "fallbacks": [
    {
      "host": "codex",
      "model": "configured-default",
      "on": ["unavailable", "capacity"]
    }
  ],
  "capacity_policy": {
    "strategy": "fallback",
    "max_attempts": 2,
    "backoff_ms": 0,
    "allow_cross_host": true
  }
}
```

Without this explicit declaration, execution returns `paused` with a resume command.

## Model and report binding

Codex model names resolve conservatively against the local catalog: exact slug, normalized name, unique alias, then bounded typo correction. Numeric versions never drift. Other hosts accept safe literal IDs when no catalog adapter exists.

State, report, and telemetry keep:

- requested and resolved model;
- resolution strategy;
- reasoning effort when supported;
- host and fallback history;
- feature, run, attempt, agent/lane, writable roots, and declared lane paths.

Reports that do not match the registered attempt are rejected.

## Review policy

`aioson verification:plan . --feature=my-feature --trigger=per-phase` runs no reviewer by default. At `end-of-feature`, QA is the only default reviewer. Tester, Pentester, and Validator run only when their manifest entry is enabled and its trigger applies.